Lip Seals are custom engineered to have a tall, thin profile with a notched “lip” area, giving it a few advantages in sealing over an O-ring.
The resilience quality of an elastomeric material will be the same for a Lip Seal as an O-ring. However the main feature of a Lip Seal in an axial application is the flexible lip. This lip can compensate for both large tolerances and the existence of a gap between the sealing surfaces. The notch or “lip” is designed to face the pressure source, which benefits the seal in two ways. First, the pressure energizes the lip to increase sealing force on the mating hardware. Second, the flexibility of the geometry coupled with the resiliency of the material will rebound to compensate for variation in the clearance gap.
These characteristics make the Lip Seal an excellent option for overcoming hardware tolerances and clearance gaps in axial applications. To see all the advantages of the molded Lip Seal, link to ISS 5807